I ; aking of 3 oS . 


AD & 


RESEARCH LIBRARY 
here GealTY RESEARCH INSTITUTE 


JOHN MOORE ANDREAS COLOR CHEMISTRY LIBRARY FOUNDATION 


COLLODION 


and the making of Wet Plate Negatives 
for Photo-Engraving Work 


A handbook of information concerning 
the production of wet plate negatives 
by simple and sure methods 


Eastman Kodak Company 
Rochester, N. Y. 


1928 


Practical Methods of Collodion 
Negative Making 


OLLODION is made by dissolving a soluble cotton or 

pyroxylin in a mixture of equal parts of alcohol and 
ether. To make this soluble cotton, absorbent cotton is 
treated with a mixture of nitric and sulphuric acids. It is 
then very thoroughly washed with water to get rid of all the 
acids, the water removed and after the cotton is thoroughly 
dry it is dissolved in the alcohol and ether, and such dis- 
solved nitrated cotton forms plain collodion. 

Collodion is used in wet plate negative making as a 
convenient medium for pouring on to a glass plate to form 
a film, porous when moist; at the same time it is a suitable 
vehicle to hold various iodides. When this film is treated 
with a silver nitrate solution, the iodides are converted to 
silver iodide which is held suspended in the collodion, and 
affords the sensitive material upon which the latent image 
is formed by exposure to light. 

Eastman plain collodion will keep indefinitely as long as 
it is not iodized, in fact it rather improves by keeping. It is 
not sensitive to light, not even when the iodizer is added. 
Only when the iodized collodion is placed in the silver bath 
is a silver iodide formed which precipitates in the collodion 
film, and this silver iodide is sensitive to light. After 
exposure has formed a latent image, the developer has the 
effect of causing the silver from the bath solution which 
remains on the surface of the film to be deposited in the form 
of metallic silver on the latent image. Fixing removes the 
iodide of silver and all that remains then is the deposited 
metallic silver image on the clear collodion film. 

It has been suggested that we describe the way in which 
Eastman Collodion should be used in photo-engraving 
work. We therefore tell in the following pages exactly how 
it is used in our own Engraving Department every day. 

There are very many different formulae for working wet 
collodion. Without saying that those we use are the best, 
we do know that they are thoroughly satisfactory and prob- 
ably as simple as any that can be worked. 

Cleanliness is essential for the successful working of all 
photographic operations, and particularly so with wet col- 
lodion. The dark-room must be kept clean and well 
ventilated, if trouble is to be avoided. This is most im- 
portant. 


COLLODTLOWN 


Preparation of the Glass 


New glass, or old negatives, if not varnished, should be 
soaked in 
Nitric Acid - -  - =. ‘= J@iarbts2ioze 
Water - - - =. - = 1 gallon (128 G73) 


Old negatives, if varnished, should be soaked in lye made 
as follows: 


Crude Caustic Sous we ie eRe 
Water - - - = = 1 gallon (128 ozs.) 

When the film is loosened, scrub it off and put the glass 
into the nitric acid solution and let it soak for a few hours, 
24 hours preferably. The plates should then be scrubbed 
under the tap with a soft scrubbing brush or pad of felt, 
and well rinsed. If the glass is not properly cleaned, fog 
and streaks will inevitably result. The glass, while still wet, 
is flowed with the following solution: 

White of one eee 

Ammonia~— - - - += 10 minims 

Water - «= = 8) = S) Sart ee 
The egg-white must be well beaten, and the solution filtered. - 
While the plate is still wet it is flowed once with the sub- 
stratum and drained, and then flowed again, drained, and 
put to dry in a dust-free place. 

Dried albumen, of which 70 grains is equal to one ounce 
of fresh egg-white, is sometimes used instead of fresh 
albumen, but some dried albumens are not suitable and the 
fresh egg-white is better. A gelatin substratum may be 
used if preferred: | 


Gelatin - -  - 150 grains 
Glacial Arete Acid - - + 150 minims 
Water - - oy) Aiea ¥% gallon (64 ozs.) 


Or Eastman Rubber Solution, diluted with benzol, may 
be used: 

Eastman Rubber Solution- - - - 1oz. 

Pure Benzol See ee en! eS 
This rubber solution can only be poured on after the glass 
is dry. 

If it is preferred not to substratum the plates they should 

be allowed to dry after scrubbing and rinsing as above, then 
sprinkled with this solution: 


Iodine - - 200 grains 
Denatured alcohol: (free from grease) ¥% gallon (64 ozs.) 


4 


CoO DEON SOLUTION 


and polished off with a piece of lintless rag or chamois 
leather. Glass that is not substratumed should be edged 
with rubber solution applied with a small brush, which is 
better than absorbent cotton. 

The glass having been prepared, it has now to be flowed 
with collodion. 


The Collodion Solution 


Eastman Complete Collodion is supplied in two con- 
tainers, one containing the plain collodion and the other the 
iodizer. The reason for this is that an iodized collodion 
gradually gets slower as it ages, but the plain collodion and 
iodizer separately will keep indefinitely, as long as the 
bottles are kept well corked. Collodion should always be 
kept in a cool place, otherwise the cork may be blown out 
and rapid evaporation goon. Add the contents of the 2 oz. 
bottle of iodizer to half a gallon of plain collodion and the 
collodion is complete and ready for use. Do not add any- 
thing else. It works best after it has been iodized a few hours, 
but it can be used at once and will keep for months without 
losing very much speed, but as it does eventually lose speed 
after iodizing, it is recommended that not more be iodized 
than will be used up in about two weeks. As this collodion 
is filtered through 14” thick filter paper under pressure, 
there is no need to refilter. But if it is thought desirable to 
filter again after iodizing, use a small filter loosely fitted 
with absorbent cotton, in order to minimize evaporation. 

Eastman Complete Collodion is equally suitable for 
either half-tone or line work. 


If Collodion is Too Thick 


Eastman Complete Collodion will never be found too 
thin, but if a thinner collodion is required, add a mixture of 
equal parts of pure grain alcohol and ether to the plain col- 
lodion and then add 2 ozs. of iodizer to every half gallon of 
the thinned plain collodion. If a thinner and also softer- 
working collodion is required, use Eastman Special Iodizer, 
which contains more solvents as well as iodizer of a different 
formula. Take 1 part of this to 2 parts of Eastman Plain 
Collodion, this makes a collodion half again as thin. 

Eastman Special Iodizer may also be used to thin down 
regularly iodized collodion that has become too thick from 
evaporation of the solvents. 


5 


COLE OD Toa 


As Eastman Collodion is made up in very large quantities 
each time, under the most rigid tests at every stage, it will 
be found to be uniform. If you find any differences in work- 
ing, you may be fairly certain it is not due to the collodion, 
but that some other condition under which you are working 
has been changed. 

This collodion is equally good for line work and half-tone 
work. It is a mistake to suppose that different collodions 
are required for line and half-tone work. A half-tone screen 
negative is exactly the same as a line negative inasmuch as 
the black dots have to be as dense as possible and the clear 
spaces quite transparent. If the collodion is good for line 
work, it is also good for screen negative making and vice 
versa, though if you have both old and new collodion, use 
the old for line work and the new for half-tone, because the 
new collodion is faster. 

If using a freshly iodized collodion for line work, be 
careful not to over-expose. To get the best results with fine 
line work, use the collodion after it has been iodized for some 
time and is well ripened, and use a weaker silver bath. 

Before coating a plate, it should be first carefully dusted 
with a camel’s hair brush kept specially for the purpose. If 
the brush is not clean it may leave more dust on the plate 
than it takes off. Never leave this brush lying on the bench, 
but keep it hanging up. 


The Operation of Coating 


Hold the plate horizontally either on a holder or with one 
corner resting on the two first fingers of the left hand and 
held down by the thumb. 

The collodion bottle is taken in the right hand and the 
collodion is poured in a pool on the upper part of the plate, 
the right top corner being covered during the pouring and 
the plate gently tilted so that the left top corner is next 
covered, then the left bottom corner and finally the excess of 
collodion drained off at the right bottom corner. During 
these operations, the bulk of the collodion should be kept 
well in the middle of the plate, which is only tilted suf- 
ficiently for the collodion to flow to the edge, but not over it 
and off the plate. At all points, care must be exercised that 
the edge of the collodion is kept flowing forward all the time 
and that no flow-back occurs; otherwise the collodion will 
thicken and cause a mark in the negative. The draining of 


6 


Pera UNG THE PLATE 


The wrong way to commence to drain The right way to commence to drain the 
the excess collodion from the plate, excess collodion from the plate, which is 
which is tilted too much kept as nearly horizontal as possible 


the excess of the collodion should be done very gradually into 
a wide mouthed bottle, the plate being tilted only slightly at 
first, and then being gradually brought up to a vertical 
position. During the whole of the draining, the plate must 
be rocked through almost an entire right angle, so that the 
collodion flows down toward the edges of the plate, and 
then to the corner, rather than immediately toward the 
corner. Ribbed markings are nearly always caused by 
hasty and improper draining of the collodion. As the drain- 
ing is completed and the plate becomes more and more ver- 
tical, the excess bottle should be moved with the plate, not 
scraped against it. Care should be taken to pour just the 
right quantity of collodion upon the plate, for the size being 
used. Any excess of the correct amount will cause the plate 
to be tilted too steeply and produce striation, besides wast- 
ing the collodion that drips over the sides of the plate. 

When the film has set, which is ascertained by touching 
one of the thickened edges with the finger, the plate is 
immersed at once in the silver sensitizing bath. It is impor- 
tant to do this at once in hot weather for, if delayed, the 
end first flowed will dry up and refuse to sensitize. 


7 


COLL ODITON 


The Silver Bath 


The silver bath being the most important solution used in 
the process, great care should be exercised in its preparation 
and use. Cleanliness is essential. Keep all dust and con- 
taminating substances away from the bath. Have the dark- 
room clean, thoroughly well ventilated, and free from dust 
so that the bath may be left uncovered without any danger, 
as this allows the collodion solvents in a used bath to evapo- 
rate to some extent. Use Eastman Silver Nitrate, the purest 
silver nitrate possible to procure. 

Make up the following bath: 


Eastman Silver Nitrate - 10 ounces 
Distilled Water - - 3 quarts, 14 ozs. (110 ozs.) 
Potassium Iodide - - 5 grains 


If this bath is tested with a silver solution hydrometer, 
sometimes called an argentometer or actinometer, it will be 
found to register 40 (i. e., the number of grains per ounce), 
which is a strength generally preferred for half-tone work. 
For line work, a weaker bath is better, and if instead of the 
amount of water given above, 1 gallon is taken, this will 
give a bath containing 35 grains to the ounce which is a good 
strength for all ’round work. A common practice, to which 
there is no objection, is to omit the iodide and allow a col- 
lodionized plate to remain in the bath for a few hours. If 
distilled water cannot be obtained, tap water may be used 
and the bath after dissolving set out in the sunlight until the 
cloudy precipitate is settled. The bath should always be 
stood in the sunlight when not in use, and any organic matter 
will then be reduced as a black precipitate. Make enough 
solution for two baths, so that one is always out in the light 
when the other is in use. When ready to use the bath, filter, 
and add 10 minims of pure nitric acid, just enough to make 
the bath acid, but not too strongly acid. A bath can be 
tested for this with litmus paper; it should turn blue litmus 
paper gradually red. If it turns red litmus paper blue, then 
acid must be added. 


Be sure to have a big enough vessel for the silver bath, 
and enough solution to allow some movement while in the 
bath to the largest plate it is required to sensitize, other- 
wise streaks are bound to occur. Keep the bath cool, as if 
too hot fog is probable, and be particular to see that the 
bath is not contaminated with fumes. The fumes from burn- 
ing coal gas are almost certain to cause black spots. 


8 


fee LVR Re BAT H 


Treatment of the Silver Bath 


The bath should not be tinkered with. A bath made as 
directed, used for Eastman Collodion, will keep indefinitely. 
When it gets over-iodized pour into a clean, clear glass bottle 
containing about one-third water, which will precipitate the 
excess of iodides. Now test with the hydrometer, and add 
silver nitrate until the hydrometer reads 40 (or 35 if that 
is the strength used). Neutralize acidity by putting in a 
crystal of carbonate of soda. Then stand in the light until all 
the precipitate has settled, filter, re-acidify with pure nitric 
acid and the bath is ready for use. When Eastman Silver 
Nitrate is used, unless the bath has been over-acidified, neu- 
tralization with the soda may be omitted, and then it will be 
unnecessary to re-acidify the bath. If the bath gets over- 
loaded with alcohol from the collodion plates sensitized in it, 
put into an evaporating dish and boil down. When nothing 
else is wrong, only about one-third need be boiled away, but 
if the bath is giving fog through the presence of organic 
impurities, it should be boiled down until it forms a pasty 
mass, the heat continued until it becomes liquid again and 
then allowed to cool. The resulting fused silver nitrate is 
dissolved in some distilled water, and this poured into the 
quantity of water required to make the bath to its original 
volume, tested with the hydrometer, made up to strength 
with silver nitrate and stood in the sun for a few days. 
Filter and acidify, and the bath is again ready for use. 


If negatives are not right, seek other causes before deciding 
it is the bath. Is the glass quite clean? Is the air of the dark- 
room fresh and free from dust? Is the developer right? 
Suspect the bath last, and in any case it is best to avoid the 
addition of various chemicals sometimes recommended. 
They are never necessary, as any bath, if out of order, can be 
put right by sunning, or by boiling down. If these simple in- 
structions are attended to, there will never be any trouble 
_ with the preparation of wet collodion plates, assuming, of 
course, that Eastman Complete Collodion and Eastman 
Silver Nitrate are used. 


The Right Amount of Iodizer 


When a collodionized plate is put into the silver bath, the 
silver nitrate combines with the iodides in the collodion 
and forms silver iodide. This gives a creamy film and some- 


9 


COLLODION 


times operators think that the whiter the appearance of the 
plate in the bath, the better their negatives will be, but this 
is not so. 

There is a certain amount of iodides in the collodion 
that will give the densest image. This amount is contained 
in the Eastman Iodizer; more iodides will not give any better 
negative and therefore the extra iodides, although they 
make the plate look whiter in the bath, have no good effect 
at all, but rather a bad effect, inasmuch as they consume 
the silver nitrate and make the bath become over-iodized 
more quickly than is necessary. When a bath has become 
over-iodized, silver iodide will precipitate on the plate as a 
sort of sandy deposit and these particles wash off on develop- 
ment, leaving a granular negative with pinholes. Pinholes 
are also caused in an unused bath that contains no iodide at 
all; they are caused by the iodide being eaten out of the 
collodion film to satisfy the affinity of the silver bath for 
iodide. This trouble however would not last for more than 
the first or second plate in any case. 


Sensitizing the Plate 


The plate must be immersed in the bath solution in one 
even action, so that the solution flows on the plate without 
any stoppage, otherwise a ‘“‘bath mark” line will show 
in the negative. The plate is gently moved (or if a tray is 
used the tray rocked) immediately on placing in the bath, 
and is better occasionally moved (or the tray rocked) during 
sensitizing which should be completed in about 3 minutes. 
If the bath is alcoholic, leave the plate in for about one 
minute after all greasiness has disappeared. Take the plate 
out of the silver bath, allowing as much solution to drain 
back into the bath as possible, and, being careful not to let 
anything off the hands get onto the plate or into the silver 
bath, stand the plate on a piece of clean blotting paper and 
wipe the back with blotting paper or lintless rag. Provide 
the dark slide with a strip of blotting paper on which to 
stand the plate to absorb the silver drainings which are 
corrosive and soon ruin woodwork with which they come in 
contact. Plate holders should be wiped over carefully with 
a damp rag at the end of the day’s work, and all parts on 
which silver drainings are liable to touch should be coated 
with shellac once a month. 


10 


DEVELOPING AND FIXING 


Development 


After exposure the plate is developed, a suitable developer 
being: 


Iron Sulphate wit ee eA OS, 
Glacial Acetic Acid - - - 4ozs. 
Water - - - - - - ¥& gallon (64 ozs.) 


More acid may be added in hot weather up to another two 
or three ounces, if there is any tendency to fog. 

A small quantity of denatured alcohol may be added to 
the developer if the bath is old and plates tend to repel the 
developing solution. Cover the plate with developer without 
any stop or it will leave a mark. Do not use more developer 
than is necessary, because as little silver nitrate solution 
should be washed off the surface of the plate as possible, 
since the strength of the image depends upon the amount 
of silver left on the top of the plate. Exposure should be 
such that a good image is obtained with a development of 20 
to 30 seconds. If the development veils the plate, over- 
exposure is indicated; on the other hand, forcing develop- 
ment causes grain in the clear spaces. This and over-intensi- 
fication will cause ‘‘dry effect’’ and possibly film splitting, 
especially if the glass was not thoroughly clean. 

Do not trouble to look at negatives with a magnifying 
glass during development, as, if the exposure is incorrect, you 
cannot make it right in development. After development 
the developer must be thoroughly washed out of the collo- 
dion, otherwise it will cause a stain on the negative. Wash 
at least 20 seconds under a good stream of water, and longer 
if any tendency to stain occurs. 


Fixing 

A 10% solution of potassium cyanide (30%) is flowed 
over the plate to fix. If a tray is used the plate should be 
left in twice the time it takes the white silver iodide to dis- 
appear. If a plate is left too long in the cyanide, the fine 
detail will tend to be dissolved away. If potassium cyanide 
cannot be procured, sodium cyanide will do equally as well. 
Both are deadly poisons, and bottles containing cyanide solu- 
tions should be conspicuously labelled “‘ poison. ”’ 


Potassium or Sodium Cyanide - 2 ozs. 
Water 2 im i? em SY =e TL quart. (32 ozs.) 


If 90% cyanide is used, take 3 quarts of water instead of 
one. 


11 


COLLODION 


Hyposulphite of soda 12 ozs. to 32 ozs. water may be 
used. It is just as efficient as cyanide but is not quite so 
instantaneous. Wash well after fixing. 


Intensification 


The commonest intensifier is Copper-Bromide and Silver. 
Make two solutions: 3 


No. 1 Copper Sulphate - = - 
Water to make upto - 
No. 2 Potassium Bromide : 
Water to make upto - 


12 ozs. 

% gallon (64 ozs.) 
6 ozs. 

¥% gallon (64 ozs.) 

When dissolved, mix the two solutions and the bath is 
ready. The plate is placed in the solution until it is bleached 
white right through; it is then washed for not more than one 
minute, care being taken not to allow the water to run only 
on one spot. The plate is well drained and blackened by 
pouring over 

Silver Nitrate - << «= + 98 =S 0) [gg 
Water to make up to = 8! a a ae 

Freshly made silver solution for intensification will often 
give streaks, but the addition of a few drops of nitric acid 
will insure its working smoothly. 

The washing, before blackening, must not be too pro- 
longed or the plate will not blacken. On the other hand, if it 
is not washed long enough, silver bromide will be pre- 
cipitated by the silver nitrate solution. 

If the negative is not sufficiently dense it may be inten- 
sified a second time, proceeding as above. 

The silver solution should be of the strength given, as 
the use of a weak silver solution for intensification will 
give trouble in reducing. The plate may reduce suddenly 
and unevenly. 


To Get Maximum Intensification 


To get the utmost intensification the following intensifier 
can be used. 
Lead Nitrate - 
Potass. Ferricyanide 3 ozs. 
Glacial Acetic Acid 3 ozs. 
Water to make up to ¥% gallon (64 ozs.) 
The plate is placed in this until the color is evenly yellow 
right through, it is then washed thoroughly and flowed with 


12 


3 ozs. 


INTENSIFICATION AND REDUCTION 


a weak nitric acid solution (1 to 30), rinsed again and black- 
ened with 


Sodium Sulphide Sn en Oe OBR, 
Water to make upto - - - 4% gallon (64 ozs.) 


or ammonium sulphide may be used if there is no 
objection to the unpleasant smell. The plate is once more 
rinsed and again flowed with weak acid, rinsed and then 


flowed with gum arabic or weak glue solution, to protect 
the film. 

Any necessary reduction of the negative to be intensified 
with lead ferricyanide must be done before it is intensified 
as it cannot be done afterwards. 

Sometimes for fine line work, the mercury intensifier is 
used. 


Mercuric Chloride i toe - 50ozs, 
Ammonium Chloride - - - 30ozs. 
Water to make upto - - - ¥& gallon (64 ozs.) 


The bleaching of a wet plate negative in this solution is 
slow, but it may be hastened by warming the solution. After 
thorough washing, the blackening is done with: 


Ammonia Water - - - -  30ozs. 
Water tomake upto - - - _ 1 quart (32 ozs.) 


Any reduction necessary in this case should also be done 
before the intensification. 
Reduction, Cutting or Clearing 


The usual method of reduction is to bleach the plate 
after intensification in the following solution: 


Potassium Iodide Ee Fa ei et ee OLE. 
Iodine resublimed ae vert an = ape a OSs 
Water to make upto - - - % gallon (64 ozs.) 


After bleaching it is flowed over with a weak solution of 
cyanide. 
Potassium or Sodium Cyanide - 1 oz. 
Water to make upto - “- - & gallon (64 ozs.) 
The negative must be carefully watched during this 
operation as it is very easy to over-reduce and so ruin it. 
Some operators prefer to reduce with one solution, adding 
the iodine solution to the cyanide, pouring the combined 
solution over the negative. 


13 


COLLODION 


In the absence of iodine solution, reduction may be 
effected by using the copper-bromide solution for a bleaching 
bath, followed by weak cyanide solution. 


After the reduction is complete, the plate is rinsed and 
flowed with a weak solution (1 to 20) of nitric acid and 
finally blackened by flowing over with 

Sodium Sulphide - - - - 4o0zs, 
Water to make upto - - - ¥% gallon (64 ozs.) 

If there is any sign of yellow stain, it is removed by flow- 
ing with weak nitric acid solution, the plate is then flowed 
over with gum solution: 

Gum Arabic ce Bisp ue - loz. 
Water - - 1 quart (32 ozs.) 

Sometimes Farmer’s Reducer is used. 

This is made as follows: 


No. 1 Hypo ~ a) ee a eee 

Water - = - 1 pint (16 ozs.) 
No. 2. Potass. Ferricyanide - ‘thew 

Water - - = = 1 pint (16 ozs.) 


Take the No. 1 solution and add an equal amount of 
water, then add enough of the No. 2 solution to make it 
orange colored. Use immediately as it will not keep mixed. 
The plate will require thorough washing after the use of this 
reducer. 


Stripping 

To reverse a negative, or transfer a number to a large 
piece of glass, negatives are stripped. 

After thorough drying, and when cool, the negative is 
flowed over with rubber solution. Eastman Rubber Solution 
is prepared ready for use and is exactly right for the purpose. 
It is intentionally made thin. When the rubber is dry the 
plate is coated with Eastman Stripping Collodion, which is 

plain collodion containing a small quantity of castor oil. 
~ Do not condemn Eastman Stripping Collodion should it 
be somewhat thinner than other stripping collodions. Pro- 
vided it is tough and flexible the thinner it is the better, as 
it is easier to flow and quicker to dry. When the film is dry 
it is cut around with a knife and the negative put into 
Glacial Acetic ee - = = 2ozs. 
Water - - - - = 1 quart (32 ozs.) 
until the film commences to lift. Remove the plate from the 
bath and lift up the film by the corner with a pocket knife 


14 


STREP PLEN.G 


and transfer to position required, turning over if necessary. 
To be quite sure film is not damaged or stretched, it may 
be handled on paper. Thoroughly wet a piece of thin paper 
so that all stretch is taken out and bring into contact by 
means of rubber roller or other squeegee. Lift one corner of 
the paper and with it a corner of the film which may be 
started with the point of a pocket knife, and the paper 
and film drawn off together. For reversing, the film is 
now transferred to another piece of paper, the paper and 
film trimmed with scissors and then laid on to glass, prefer- 
ably moistened with a little gum water. If not to be 
reversed, the transfer to the second piece of paper is of 
course omitted. The film can be squeegeed down evenly by 
stroking with a few pieces of 3” x 3” hard blotting paper, 
or a piece of velvet rubber. If the latter is used, keep in 
water when not in use so that it remains soft and pliable. 


Blisters are caused by pouring the stripping collodion on 
when the plate is too warm, or heating the plate too much 
before collodion has set, or having air-bells in bottle con- 
taining the collodion. Be sure to have the negative quite 
dry before applying rubber or stripping collodion. 


Stripping Simplified 


With Eastman Negative Collodion it is possible to dis- 
pense with rubber and collodion, as the negative film itself 
is tough enough to be stripped without any strengthening. 
After the negative is dry the film is cut around, and a piece 
of paper placed on that has first been well wet with 5% 
Acetic Acid Solution. After the film is loosened it is trans- 
ferred as described above. 


Sometimes negatives are varnished to protect them, 
Eastman Engraver’s Hard Varnish being used. 


_ Negatives from which many prints are to be made should 

be protected. A good plan is to cover them with No. 1 
Kodaloid, a thin transparent sheet that can be fastened to 
the corners of the negative with Eastman Film Cement. It 
is easily replaced if it should be damaged. 

Negatives which it is advisable to keep, should be 
stripped on to Kodaloid No. 6. This is light, unbreakable, 
occupies little space for storage, and the negative is instantly 
available at any time for reprinting, just as easily as though 
it were on the original glass. 


15 


COLLODION 


Defects 


Do not blame the materials until you are quite sure that 
there can be no other cause for defects. All Eastman goods 
are made up in very large quantities under the most rigid 
tests at every stage, and it is unlikely they should be at 
fault. 

The following are some of the commonest causes of 
defects met with in wet collodion work. Some other possible 
defects have been dealt with in the foregoing text. 


DIAGONAL RIBBING OR STRIAE. This is caused by rocking 
the plate through too narrow an angle when coating it, or 
not rocking enough. The plate should be coated with just 
about the right quantity of collodion, flow it slowly and 
evenly over the plate, and allow most of the excess to drain 
off while the plate is almost horizontal. If the draining is 
too rapid at first, the coating is very likely to become 
thinner at the top and thicker at the bottom, and so gives 
uneven negatives, and if in addition it is brought too quickly 
to a vertical position, and rocked rapidly through a narrow 
angle (instead of slowly through a right angle) the film will 
almost inevitably show ribbed markings. See illustration on 
page 7. If the collodion is too thick, it should be thinned 
before iodizing or Eastman Special Iodizer be used. Always 
keep collodion tightly corked, or it will thicken by evap- 
oration. 

OTHER STREAKS may be caused by removing the plate 
from the bath too soon, especially if the bath has become 
loaded with alcohol. Scum on the bath, bubbles, or dust in 
the collodion will also cause streaks. Dirty glass will also 
cause streaks. Stopping the even flow of the bath over the 
plate when sensitizing, or the even flow of the developer 
when developing will cause streaks. | 


CoLLop1ion Founp Stow. Eastman complete collodion is 
as fast as, or faster than, any collodion procurable. If it 
has been iodized for a very long time it will be slower than 
when freshly iodized; do not iodize too much ata time. 
Before it is condemned as being too slow, make sure that 
it has had a fair trial. 

Make sure your lights are right, your lens is clean, and 
developer correct; test it against some other collodion under 
exactly the same conditions when it will be found at least 
as fast. Compared with any other collodion under exactly 
the same conditions it will never be found slower. 


16 


[ 
fees TS AND REMEDIES 


Cottopion Too Sort. This is sometimes found in condi- 
tions of high temperature with much humidity. Some oper- 
ators find that collodion resumes its quality if it is kept cool, 
by placing on ice. 


PLATE Too BLuE On Takinc Out oF Batu. See para- 
graph on page 9, ‘‘the right amount of iodizer.’’ Make sure 
you have the right amount of iodizer. Do not thin down 
iodized collodion with solvent and forget to add more 
iodizer. 2 ozs. of Eastman Iodizer to every % gallon (64 
ozs.) of collodion is necessary but this is all that is necessary. 
With this amount of iodizer, if you think the plate is too 
blue, try an exposure; you will find that you will not get 
more density even if you put in more iodizer. 


SILVER SOLUTION REFUSES TO BLACKEN negative after 
bleaching in copper bromide. The cause is silver nitrate 
solution is too weak or insufficiently acid, or the bleached 
image has been washed too long. 


UNEVEN NEGATIVES may be caused by: 
1. Uneven coating. 


2. Placing plate in silver bath after the collodion has 
been set too long. This produces insensitiveness at the 
edges and may also cause the film to become contractile and 
so split on drying. The moving of the plate or rocking of the 
bath should not be in one direction only, especially if it 
contains much alcohol, as this may produce long streaks. 


3. By not allowing the developer to flow evenly over 
the plate, or pouring on one spot, or allowing it to remain 
on one part longer than another. Keep the plate moving 
gently and pay special attention to see that the developer is 
kept evenly distributed over the plate. 

4. By leaving in too strong a fixing solution. 

5. Constantly pouring the reducer on one side of the film. 

Har Tone Dots Fuzzy. Due either to incorrect relation 
between screen separation and stop size, or insufficient 
exposure. 

GRAIN ON THE NEGATIVE. Caused by too prolonged 
development. It is noticeable in under-exposure, where 
the temptation is to force development. Developer too 
strong in iron sulphate will also cause grain. Use the 
formula on page 11. 


17 


COLLODIGS 


Scum ON NEGATIVE. Usually due to dirt somewhere. 
Glass not properly clean, silver bath dirty, dark slide dirty. 
If scum is evenly all over surface it may be due to high 
temperature of dark-room, insufficient ventilation or de- 
veloper insufficiently acid. 

Foc. A reduction of metallic silver on parts of the nega- 
tive which should be clear, may arise from a variety of 
causes. It is shown on the negative by a gradual or, in some 
cases, by a sudden darkening all over the film or it may only 
spread over a small portion. Some of the causes are: 


1. An insufficiently acid state of the silver bath is one of 
the most frequent causes of fog; if the bath is suspected, 
test it with blue litmus paper and should it be in this state, 
the litmus paper will only slightly discolor. Add,drop by 
drop, a 10 per cent. pure nitric acid solution to the bath 
solution until it turns the blue litmus paper a decided red 
color. But too much acid prevents the bath sensitizing 
at all. 

2. By light making its way to the plate through cracks 
in the bellows of the camera, and also by internal reflections. 
Cracks can be located by placing one’s head in the back of 
the camera and covering the space between the camera and 
the head with a focussing cloth, thus excluding all light. 
When the eyes have become accustomed to the darkness, 
any cracks will reveal themselves. 


3. Unsafe dark-room illumination. Coat and sensitize a 
plate in the shade, expose half to the lamp suspected, keep 
the other half covered, develop, and if the light is unsafe the 
exposed part will show fog. The yellow light employed in 
a wet plate dark-room may be bright, but must not contain 
any blue, violet or ultra-violet light. Wratten No. 0 Safe- 
light fulfils these conditions. 

4. Fumes of some chemicals, turpentine and fresh paint 
are liable to produce fog, as also is smoke. Ammonia and 
ammonium sulphide fumes sometimes make their way into 
the dark-room and cause fog. Fumes from burning gas or 
electric arcs may cause fog. Keep the dark-room well 
ventilated and prevent any fumes from entering if possible. 

5. Dirty glass, new glass that has not been sufficiently 
soaked in acid, imperfectly cleaned dry plate glass, a dirty 
wash-leather or cloth. Clean these latter by soaking in soda 
solution and rinse in clean fresh water; do not use soap. 
The fog arising from this cause may be generally detected 


18 


DEFECTS AND REMEDIES 


by examining the back of the plate, when a peculiar irides- 
cent appearance may be seen. Decomposed albumen solu- 
tion used for substratum may cause fog. Some albumen 
substitute or dried albumens are not suitable for substratum 
and always cause spots and fog. Use fresh egg-white. 

6. Impure solvents employed in making rubber edging 
solution will show a fog which commences from the edge of 
the plate and gradually spreads toward the center. Use 
Eastman Rubber Solution. 

7. Aprons upon which Sodium Sulphide or Ammonia 
have been spilt will cause, especially in hot weather, a fog 
to appear on that side of the negative that has been held 
near the body. Fingers stained with these chemicals will 
give fog in the portions of the plate which they have been 
near. 

8. Some collodions when freshly iodized have a tendency 
to give fog; should this be the case, add a few drops of a 10 
per cent. solution of iodine in alcohol until the collodion 
assumes an orange color, or place aside to ripen. An iodized 
collodion of a light yellow color is more liable to fog than 
one of a darker orange or red color; the former is, however, 
the faster working of the two. There is no danger of fog 
when using Eastman Complete Collodion, nor any necessity 
to add iodine to it. 

9. A developer lacking in acetic acid, or one that is too 
warm or too strong. Use the formula on page 11. 

10. A new bath will sometimes give a surface fog which 
can be removed with a pad of absorbent cotton applied with 
care to the surface of the film while the water is running upon 
it. If this is at all troublesome, add a little more acid to the 
developer. 

11. The use of impure chemicals will cause fog. Use 
Eastman Tested Chemicals. 

12. One of the worst causes of fog, because usually un- 
suspected, is insufficient ventilation in the dark-room. 

“Dry Errect’’ (so called). A relief appearance of the 
image on the negative after it is dry, making it difficult to 
strip and difficult to print, is due entirely to excessive in- 
tensification. If sufficient exposure is given so that only a 
normal intensification is needed, this effect will not occur. 

GrounpD GLass EFFECT or graininess is caused by under- 
exposing and forcing development. The remedy is to give 
more exposure and shorten development. 


19 


COLO DOs 


SPLITTING NEGATIVES are due to too much intensification. 
Fine cracks after lead intensification may be caused by 
collodion being too thick. Thin the collodion, give full 
exposure and short development. See that substratum is 
not too weak. If collodion is allowed to get too dry be- 
fore sensitizing it may crack. 


With some collodions splitting may occur through the 
solvent being too anhydrous, but this will not be the case 
with Eastman Complete Collodion, as solvents are carefully 
tested before use. 


BLISTERS OR BUBBLES when stripping. Due to putting 
rubber solution or the stripping collodion on the plate when 
too warm. 


Brack Spots AND Comets. Due to dust falling on the 
plate before or after albumenizing, while being coated, or 
already in collodion. Developer not being filtered. Dried 
particles of collodion especially from mouths of dirty col- 
lodion bottles. Dry plate developer dust floating about 
the room produces very bad spots. Chemicals should 
never be mixed in sensitizing room. Coal gas being burned 
nearby will sometimes cause spots. Be most particular to 
have the dark-room thoroughly well ventilated and kept free 
from dust. Sulphur from hard rubber dipper is said to cause 
spots. Varnish the dipper with shellac. Sometimes wooden 
or composition baths used as containers for the silver bath 
will cause spots. See that the shutter of the plate holder 
does not grind; if so, this may cause dust to settle on the 
plate and give rise to spots. Building operations in the 
neighborhood are liable to cause spots. Use muslin over 
the open windows. 

FinE Brack LINEs are caused by scratches in the glass 
which has not been sufficiently cleaned. They may usually 
be removed by turning over the negative film and wiping off 
with a piece of wet cotton. But see that the glass is more 
thoroughly cleaned to prevent this defect: 


SMALL TRANSPARENT Spots (PINHOLES). Due to bath 
being over-iodized. A somewhat less definite spot may 
result from an under-iodized bath. Hypo dust will cause a 
transparent spot. Keep solid hypo out of the room, and do 
not let any hypo solution fall on the bench or floor to 
crystallize. 

Brown STAIN ON BLACKENING WITH SULPHIDE. This 
is generally due to insufficient washing between developing 


20 


fee CPS AND REMEDIES 


and fixing, but it may be caused by using a stale and 
exhausted fixing bath. 

A BuLUvE Srarn after bleaching with lead is due to insuf- 
ficient washing after development. 


AN OPALESCENT STAIN is produced by insufficient fixing. 


IRREGULAR CLEAR Marks. Produced by plate being im- 
mersed in silver bath before collodion has set, the water of 
the bath precipitating the cotton. 


SHARP LinE Across Prater. Bath marks made by the 
first flow of the sensitizing solution not completely flooding 
the plate, or a stoppage of the developer when flowing over 
the plate. 


MOoTTLING AND STREAKS. Sometimes caused by not rock- 
ing or moving sufficiently during sensitizing. 

METALLIC STREAKS. In very cold and dry weather 
streaks are caused with a collodion that has been made with 
solvents that are too dry. Try adding a few drops of 
water. 


‘““OySTER-SHELL”’ Marxincs. Generally due to one of the 
following: 


Dirty plate holder (the plate holder should be wiped out 
_ every day with a wet cloth and once a month varnished 
inside with shellac varnish). Dirty or sodden blotting paper. 
Insufficient draining when removing plate from silver bath. 
They are very liable to show with a new bath. Add a little 
old bath to the new one if you have it. Usually a longer 
draining of the plate, rocking it at the same time, will 
avoid oyster-shell markings. | 


Firms REFUSING TO Strip. Due to dirty glass, or impure 
Rubber Solution. Use clean glass and Eastman Rubber 
Solution. More acetic acid must be used in which to soak 
old negatives; it is sometimes impossible to strip a very 
stale negative. 


FILMS NOT STICKING AFTER STRIPPING. Due to grease 
on glass, or impurities in stripping collodion. Use clean 
glass and Eastman Stripping Collodion. 


PREVENTION Is BETTER THAN Cure. The list of defects 
seems formidable, but there will seldom, if ever, be any 
defects if the methods described are followed. Cleanliness 
especially should be practiced. Let the dark-room have 
frequent doses of fresh air, and daylight if possible. Use 


21 


COLLODION 


Eastman Complete Collodion, Eastman Silver Nitrate and 
other Tested Chemicals and troubles will be as unknown as 
they are in the Eastman Engraving Department. 


Part of the Eastman Service 


Because it gives opportunity for testing materials, under 
the same conditions that the photographer meets, we have 
conducted our own photographic developing, printing and 
enlarging department for over thirty years. This depart- 
ment uses Eastman goods exclusively and thereby gives a 
double check on the practical utility of our products. It 
backs up theory with practice, and if goods which have been 
passed by our testing departments fail to hold up to the 
required standards, we know it quickly—not from the out- 
side, but from our own experience in this separate depart- 
ment within our own walls. 


But there is even a greater advantage than this. We 
learn by experience practical short cuts, and how to main- 
tain efficiency, which information is passed on through our 
printed matter, through our correspondence and by actual 
demonstration to our customers right here in the department, 
as part of the Eastman service. 


Because this Photographic Finishing Department has 
proved so valuable to our customers, and ourselves, we in- 
stalled our own Engraving Plant. It has only one customer, 
the Eastman Kodak Company, but that one customer has 
enough work to maintain the plant on a commercial scale. 
It has to meet the every-day problems that all engravers 
meet and so is in a position to know our goods by practical 
test. It has therefore been of the utmost benefit to us in 
making our products right. But it goes beyond that: it is at 
the service of the photo-engraver, employer or workman, 
who needs information on any photo-engraving problem, 
whether he uses Eastman materials or not. It is a part of 
the Eastman Service. 


EASTMAN KODAK COMPANY 


RocHEsTER, N. Y. 


Paes 


PRICE LIST 


All prices are f.o.b. shipping point and subject to change 
without notice. 


Bottles and cans are not charged and are not returnable. 


Interstate Commerce Commission Regulations provide 
that collodion may not be sent by express in bottles larger 
than one quart, though 20 quarts may be sent in one out- 
side container. But boxed cans may go by express in any 
size up to 5 gallons. Collodion or Collodion Cotton cannot 
be sent by parcel post. 

Do not be afraid to order Eastman Collodion in cans, as 
we make our own cans especially for it, and we know they 
are satisfactory. 


Eastman Complete Collodion 


Plain Collodion not iodized but with lodizer in separate 
bottles; only requires adding the accompanying Iodizer to 
Collodion to form Complete Collodion: 


Rochester 

Chicago & San Francisco 

New York 
In 1 quart bottles = op eee te guns: a bry Al $ 1.50 
In % gallon bottles orcans -— - 2.20 2.65 
In 1 gallon bottles or cans Sia 4.00 4.70 
In 5 gallon cans Pe Tea Fk ak 5 fom 18.00 21.35 


Eastman Plain Collodion for Negative Making 
Eastman Cotton dissolved in pure alcohol and ether, 
without [odizer: 


In 1 quart bottles ap har $ 1.00 $ 1.30 


In % gallon bottles or cans ma hoe 1.80 2020 
In 1 gallon bottles or cans - 3.50 4.20 
In 5 gallon cans Sh es) ke 16.00 19.45 


Eastman lodizer 
Used with Eastman Plain Collodion will give a collodion 
yielding brilliant line and half-tone negatives. 
In 1 oz. bottle (sufficient to iodize 1 cae 


of collodion) -— - $ .30 $ .35 
In 2 oz. bottle (sufficient fio iodize y% 

gallon of collodion) -— - .50 .60 
Per dozen 2 oz. bottles Sti Sarl Oh 5.50 6.00 


Eastman Special Iodizer 
For making a thinner, softer-working collodion, 1 part of 
Special Iodizer is added to 2 parts of Eastman Plain Collodion: 


In 1 pint bottles - -  - - $ .80 $ 1.00 
In 1 quart bottles Sg ere ce os te 1.50 1.80 
In % gallon bottles - - - - 2.60 3.05 


23 


COLLODION 


Eastman Cotton for Making Collodion 
A high grade, uniform product, packed in bottles and wet 
with solvent: 


Rochester 

Chicago & San Francisco 

New York 
In 1 ounce bottles oo I hn $ .30 $ .35 
In 4 ounce bottles - < - - 1.00 1.10 
In 8 ounce bottles = = < 1.50 2.00 


Eastman Stripping Collodion (Ready for Use) 
A flexible collodion of exceptional toughness: 


In 1 quart bottles or cans ~) ile ae $ 1.30 
In % gallon bottles or cans ~ 1.80 2 22 
In 1 gallon bottles or cans - = 3.50 4.20 
In 5 gallon bottles or cans - 16.00 19.45 


Eastman Rubber Solution (Ready for Use) 


Consists of pure masticated rubber dissolved in water- 
free benzol: 
In 1 quart bottles or cans 


In % gallon bottles or cans ae 1.20 1.65 
In 1 gallon bottles or cans lipase 2 an 2.95 
In 5 gallon bottles or cans =e 10.00 13.45 


Other Eastman Specialties for Photo-Engravers 
Eastman Silver Nitrate 


Taken without any discrimination from the same stock 
that we manufacture for our own use in making our high- 
speed photographic emulsions, and therefore must be of the 
highest purity. 

Packed in bottles of 1, 4, 8, 16, 100 and 200 ounce capac- 
ity. The price is based on the market price of Silver Bullion. 
A slight advantage in price is offered to purchasers of 100 
ozs., 500 ozs., 1000 ozs., and upwards. Current quotations 
will be forwarded immediately on request. 

Eastman Engraver’s Hard Varnish 

A clean quick-drying varnish that forms a tough film for 
the protection of negatives: 

1 quart $1.90 1 gallon $7.00 
Wratten Safelight Lamp 


The Wratten Safelight Lamp is radically different in con- 
struction from the ordinary dark-room lamp in that none 
but reflected light is permitted to pass. 

The electric globe is placed inside the lamp at the top; the 
upper half of the lamp being fitted with a sheet of opal glass 
(for white light illumination) which can be covered with a 
light tight shutter. 


24 


Peel Ceo Sch: 


By means of a white enameled curved reflector the rays 
of light from the lamp above are brought down and evenly 
diffused over the surfaces of the glasses comprising the safe- 
light which are fitted to the lower portion of the lamp front. 

The safelight glasses are eight by ten inches, affording 
ample illumination for the inspection of large plates. 

The Wratten Safelight Lamp is constructed for use with 
electric light only, and includes electric lamp attachment 
with six feet of cord and plug and one safelight. 

In ordering, specify which series of safelight is desired. If 
not specified, Series 2 will be furnished. Series 0 is best for 
wet-plate work. 


THE PRICE 
No. 1 Wratten Safelight Lamp (as above) - - $10.00 
No. 2 Wratten Safelight Lamp about opening 
for white light ) mech shen 8.00 


Indirect Light Boxes 


For general illumination of the dark-room, it is best to 
have a lamp box into which a Wratten Safelight is fitted, 
and to suspend it from the ceiling of the room, hanging 
down about 2 feet or 30 inches, with the Safelight towards 
the ceiling, which should be white, so that the room is 
illuminated by light reflected from the ceiling. 


THE PRICE 
Indirect light box for one 10x12 Safelight - - $9.00 
Indirect light box for two 10x 12Safelights - - 18.00 


Cord and plug are included but not safelights or electric 
bulbs. 


Wratten & Wainwright Safelights 


The safelight consists of one or two sheets of glass coated 
with a colored gelatin film, which transmits a perfectly safe 
light for handling the sensitive materials for which they 
are recommended. 

Series 00. A clear yellow for use with lantern slide plates, 
-gaslight papers, etc. 

Series 0. A bright orange color suitable for Wet Col- 
lodion, bromide paper and lantern plates. 

Series 1. An orange safelight for use with ordinary, 
medium, and rapid plates and films which are not color sen- 
sitive. Consists of yellow and orange coated glass with red 
paper between. 

Series 2. A safelight for extra rapid and orthochromatic 
plates and films which are sensitive to green but not red. 


25 


COLLODION 


This safelight consists of yellow and violet coated glass with 
deep red paper between. 

SERIES 3. A green safelight for use with the red-sensitive 
panchromatic plates and film. Gives faint illumination, 
which however is quite strong as the eyes become ac- 
customed to it. This safelight consists of yellow and green 
coated glass with green paper between. 

SERIES 4. Bright green safelight for use with ordinary 
plates for those who are unable to use a red light. Not safe 
for orthochromatic plates. 

These safelights can be used to special advantage in the 
Wratten Safelight Lamp described above. 


PRICE (any series) 
Le eal Meee geet ff 10 x 12 - - $1.75 
S10 (a eee 


Special sizes at an advance of 33144% above the price of 
next larger size from which they can be cut. 


Eastman Mono-Lock Process Printing Frame 


A convenient frame that opens or closes with one motion. 
Saves time, saves fatigue. Size to take 15” x 18” plate or 
smaller. 

Complete, with 1 inch plate glassfront - - $60.00 


Transparent Kodaloid 


Transparent film base in the (No. 1) Thinnest grade, may 
be used for protection of negatives that have to be fre- 
quently printed. The (No. 3) Heavy or (No. 6) Extra 
Heavy grade may be used as a support for stripped collodion 
negatives instead of glass, it is less expensive and occupies 
less space for storage and eliminates danger of breakage. 


THE PRICE 
No. 1 Thin -  - = <=: «= “a 9250 per gaat 
No. 2 Medium +  - -) + 9 = 25e%peraqcan 
No. 3 Heavy - = °= = 9s 306 per equi 


No. 6 Extra Heavy - 


Eastman Film 


Eastman Film possesses the following advantages: 

It affords negatives free from halation without the neces- 
sity of backing. 

Perfect contact is assured, as there is no curve as with 
the glass plate. 

The method of manufacture permits a more even coating 
than is possible on glass plates. 


26 


35c per sq. ft. 


Pokol Cok cL DST 


Many more films can be developed, fixed and washed at 
one time than can glass plates with similar equipment. 

The films can be printed from either side, making reversal 
easy. 

They are unbreakable and may be cut to any shape. 

They require but little more room for storage than so 
many sheets of paper. 

Eastman Film will be supplied in any width up to thirty- 
six inches, and in any length. 


EastMAN ‘“‘Process”’ Film for negatives or positives. 
Especially suitable for line negatives and all process 
subjects. Any desired degree of contrast either weak or 
strong may be secured with these films. 


EasTMAN ‘‘ComMMERCIAL”’ Film for negatives or positives. 
Less contrasty than ‘‘Process’”’ Film and especially suitable 
for photogravure positives. 


Prick Per DoZEN 


=i es | - - $1.45 14x17 - - $13.70 
8x 10 ae 3.20 16x20 - - 18.40 
10x 12 - - 5.60 TAR eke teem aC aU 
11x14 = =~ 8.05 20K AS hae he 227) OD 


EASTMAN ‘‘COMMERCIAL PANCHROMATIC” FILM, sensitive to 
all colors: Prick PER DozEN 


exo7 - - $1.60 14x17 - - $15.10 
8 x 10 ina s Os pO RO 0 ee ee 20625 
$0% 12 pees. -O, 20 A Shem 20; AO 
11x 14 ee, 90 20x24 - - 30.40 


Eastman Kodaline P aper. For making paper nega- 
tives. It will be found to give the greatest possible density, 
to be fast, and to be coated on an exceptionally fine- 
textured stock; in short, it has just the right qualities for 
lithographers and others wishing to use paper negatives. 
In rolls— 


10 ft.x20 in. - - $1.70 10 yds.x20 in. - - $5.10 
10 ft.x40 in. - - 3.40 10 yds.x40 in. - - 10.20 
In sheets— Sizes Dozen Sizes Dozen 
8x10 - $ .75 16x20 - - $2.80 
10x122.- 1.15 17x20" =~. 3.00 
Tixi4- 1.40 . 18x22) << 3.50 
14x17 - 2.10 20x24 - - 4.20 


Eastman Topping Powder 
For Zinc Etching. In one pound packages $1.00 each. 


27 


COLLODION 


Eastman Engravers’ Proofing Paper 
A smooth, non-glaring, pure white proofing paper that 
takes ink readily. Weight 60 lbs. per ream, or over. 
Size 20x24 inches. Per ream of 500 sheets - - $24.00 


Eastman Photogravure Tissue 


Specially suitable for Rotary Photogravure. 
In rolls 12 feet long by 36 inches wide, $4.50 per roll. 


Eastman Process Plates 


Suitable for line and half-tone work, and all subjects in 
which great contrast is required in negative or positive. 
SET oe OSS ee ae $1.45 per dozen 


8x10 - - - - - - 3,20 per dozen 
10:x 12) <6) er ok eee - _5.60 per dozen 


Color-Sensitive Plates for Engravers 


Wratten & Wainwright Process Panchromatic Plate for 
direct half-tone color work. 

Wratten & Wainwright Panchromatic Plate for indirect 
color and object work. 

These plates were the first plates highly sensitive to all 
colors, to be produced commercially. They are double 
coated to eliminate the halation which is so disturbing in 
color work. 

PricE PER DozEN 


6 55 7,: | nite el CeO 14x17 - ~- $17.25 
8x10 - - 4.00 16 x 20 - = eS 
10x12 - athe kt 18 x 22 - «5 he S 
1ix14 - =. -40.05 20 x 24 - «ho ee 


Wratten & Wainwright Color Filters 
For all purposes 


These filters are in accordance with the very latest 
scientific developments and are universally recognized as 
the best to be obtained. Wratten & Wainwright three color 
filters are standard throughout the world. 

Supplied in gelatin film, cemented in parallel plate glass 
or cemented in hand-worked optical plate of the very 
highest quality. Prices on Request. 

Those interested in three color work are requested to ask 
for our Booklet ‘“‘ Reproduction Work with Dry Plates.” 


EASTMAN KODAK CO., Rochester, N. Y. 


28 


GETTY RESEARCH INST 


NM 001 


125 01147 3 


